Mill for cold-rolling skelp



J. W. FREEx MILL FOR COLD ROLLING SKELP. APPLICATION FILED MAR. II, 1920.

3 SHEETS--SHEET FIBJI- WITNESSES INVENTOR OIL/Q2116 Patelited Apr. 5,1921.

J. W. FREE.

M |LL FOR COLD ROLLING SKELP. APPLICATION FILED MAR, II, 1920.

Patented Apr. 5, 1921.

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MILL FOR 0mm; SKELP. APPLICATI MAR: 11, I920.

1 ,374, 145. Patented Apr. 5, 192 1.

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FIELX- UNITED STATES PATENT OFFICE.

JOHN W. FREE, OF VOODLAVJN, IENNSYLVANIA, ASSIGNOR TO JONES & LAUGI-ILIN STEEL COMPANY, 01 PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENN- SYLVANIA.

MILL FOB COLD-ROLLING SKELP.

Specification of Letters Patent.

Patented Apr. 5, 1921.

Application filed March 11, 1920. Serial No. 365,009.

To all whom it may concern:

Be it known that I, J OHN W. FREE, residing at Woodlawn, in the county of Beaver and State of Pennsylvania, a citizen of the United States, have invented or discovered certain new and useful Improvements in Mills for Cold-Rolling Skelp, of which improvements the following is a specification.

My invention relates to improvements in mills for shaping pipe skelp preparatory to welding, and, more particularly, to mills for shaping such material while cold, and bringing it to tubular form with overlapped edges, ready for lap-welding. The objects are simplicity and effectiveness.

, My invention is embodied in a mill illus trated in the accompanying drawings. Figure I is a view of the mill in side elevation; Fig. 'II is a View of it in plan; Fig. III is a vertical transverse section, on the plane indicated by the line III-III, Fig. I; Fig. IV is a view in elevation ofone of the pairs of rolls detached; and Fig. V is a fragmentary view to a larger scale, showing in elevation one of the guides for the material in its advance from one roll pass to another.

Figs. VI to XII inclusive show in vertical section the successive roll passes through which the material in the course of its fabrication passes, and associated with the rolls themselves the material is shown. Above the successive roll passes of the mill as shown in Figs. I and II I have placed the numerals VI, VII, VIII, etc, thus indicating to which roll pass each sectional view belongs. I

The mill consists essentially of a succession of pairs of rolls, forming the succession of roll passes illustrated in Figs. VI to XII, inclusive. In Fig. 11 I have applied the numerals 1 to 7 to the upper rolls there shown of this succession of pairs.

These rolls, it will be observed, are arranged all of them in parallel positions in this instance they are all horizontal, and this arrangement makes possible the mounting of them all in a common frame or housing 8 and the driving of them, or at least so many of them as are power driven,

through the gear train 9 of simple arrangement, sufliciently indicated in Figs. I, II, and III. The intervals at which. the successlve roll pairs are set are conveniently short, and the mill accordingly becomes a continuous mill (there is no appreciable elongation of the material under treatment); Ordinarily, a single length of material imder treatment will in the course of treatment be engaged by all or substantially all of the shaping rolls simultaneously.

Between successive roll pairs are arranged suitable guiding means, including the idle beveled rollers 10 mounted on vertical stub shafts and placed in pairs between the passes. One of these guide rollers is illustrated in Fig. V and their positions are indicated in Figs. I and II.

At the delivery end of the mill straightening means are provided, and these preferably include a pair of rollers l1, which ordinarily need have no'capacity for relative movement, but which are mounted to rotate idly in their bearings. Their faces are properly shaped, and of a shape which will be more clearly defined in the sequel. This pair of rollers is, in order to accomplish its intended ends, mounted for adjustment as a unit, both vertically and horizontally.

Coming now to the skelp-shaping instrumentalities and their operation, the development of a skelp into a pipe blank will be sutliciently understood on careful consideration of Figs. VI to XII, with reference to the other figures to make plain the rolldriving means.

First of all, it is to be observed that a flat skelp is developed by transverse bending into a tubular blank with overlapped edges: a blank of proper shape and size, and with edges suihciently overlapped, to undergo the welding operation and produce a lapweld pipe of the intended dimensions. The bending of the blank is developed by beginning with the skelp in horizontal plane and arching it upward. The blank as, it develops is accordingly downwardly concave, and, by virtue of this position, it clears itself of scale between the roll passes.

Coming to particular definition of the roll passes, the preferred arrangement is as folfourth pass the radius of the bottom of the.

now trough-shaped blank, the middle portion of the blank, is still further reduced. The lowerfroll of the fourth pass is the last one to engage the inner surface of the developing blank; both rolls of the fifth pass engage the exterior surface, for the curva ture of the blank has now, as will be seen in Fig. IX, developed until theangular sweep of the arc which the blank forms, exceeds 180. In the fifth pass the radius is reduced throughout and made substantially uniform,

the two edges of the blank coming now into close proximity. The lower roll of the sixth pass is stepped, and in the sixth pass one edge of the blank is bent inward a distance as great as the thickness of the material, and this portion is thus brought to substantially its ultimate curvature; otherwise,there is no reduction of curvature in the sixth pass.

The seventh pass constricts the tubular blank to its ultimate dimensions, and brings the edges to the desired overlapped position.

All the roll pairs are preferably positively driven, excepting only the sixth, the pair which eifects the depression of one edge relatively to the other. I find it preferable to avoid a frictional tension of roll uponblank here; but instead mount the rolls of this pair for idle turning.

I desire to call attention to the fact that all of the instrumentalities which act upon the material while in the course of formation to tubular shape ready for lap welding act upon'it externally; there is no internal ball nor mandrel upon which the developing tube is shaped. This is a great simplification and, while my instrmnentalities'do not forbid the use of such a ball ormandrel, I consider its absence a distinct and substattial advantage, and it isa thing not known before in the preparation of blanks for lap welding.

I desire further to note that the shaping instrumentalities. engage and exert shaping stress upon and only upon the faces of the skelp, leaving the scarfed edges free of stress, free of shaping contact with roll surfaces or with one another, and so unmutilated and undamaged for the ultimate welding operation.

No claim is here made to the method of 1920, Serial No. 405,758. In the application referred to my invention in re method is claimed by myself as subject matter for Letters Patent. i

In the ensuing claims I define the essential features of my invention, leaving themecha nism in other respects subject to adaptation, as the engineer may prefer. The showing of the drawings is in those respects exemplary merely. V 1

I claim as my invention:

- 1. A skelp-bending mill wherein the shaping instrumentalities consist only and entirely of a plurality of'pairs of rolls, shaped to engage the skelp upon its faces only and in. such engagement to shape to a tubular blank with overlapped edges readyfor lapwelding a length of skelp with scarfed edges.

2. A skelp-bending mill wherein the shaping instrumentalities consist only and entirely of a plurality of pairs of rolls all mounted withparallel axes, shaped toengage the skelp upon its faces only and in such engagement bycold rolling to shape to a tubular blank with overlapped edges ready for lap-welding a length of skelp with scarfed edges. I

3. A skelp-bending mill'wherein the shaping instrumentalities consist only and entirely of a succession of pairsof rollsshaped to engage pair by pair the skelp, one of the rolls of one of the pairs other than the last having a stepped rolling face, and the rolls of the next succeeding pair, engaging the developing blank upon its external surface only, being shaped and proportioned to con strict the blank to the form of a tube with overlapped edges.

4. A mill for bendingsskelp by cold-rolling wherein the shaping instrumentalities consist only and entirely of seven pairs'of rolls, shaped to engage the skelp upon its faces and in such engagementto shape to a tubular blank with overlapped edges alength of skelp with scarfed edges, the roll passes between the pairs of rolls possessing succes 'sively the following characteristics; first,'a pass in which the skelp is bent transversely to a curve. of uniform radius; second, a pass in which the curvature of the side portions is reduced in radius and reduced in greater degree than the medial portion; third, a pass in which the curvature of the medial portion is further reduced and made of equal radius with the side portions; fourth, a pass in which the curvature of the medial portion is reduced in radius, while" that of the side portions continues unchanged; fifth, a pass in which the curvature of the side portions is reduced and made equal in radius with that of the medial portion; sixth, a pass in which one edge is pressed inward relatively to the other and reduced in radius of curvature; and, seventh a pass wherein the remainder of the article is reduced in radius of curvature.

5. A mill wherein a length of skelp is by cold-rolling brought to the shape of a tube with overlapped edges, ready for lap-welding, such mill consisting of a plurality of pairs of rolls, mounted all on parallel axes, 10 the upper roll of each pair being concave.

In testimony whereof I have hereunto set my hand.

JOHN W. FREE.

WVitnesses:

L. ARTHUR WEST, CHAS. H. MOLAUGHLIN. 

